Miscanthus can host Western Corn Rootworm

The western corn rootworm beetle, a pest that feasts on corn roots and corn silk and costs growers more than $1 billion annually in the U.S., also can survive on the perennial grass Miscanthus x giganteus, a potential biofuels crop that would likely be grown alongside corn, researchers report.

Rootworm beetle larvae can survive to adulthood on Miscanthus rhizomes, and adult beetles will lay their eggs at the base of Miscanthus plants grown near cornfields, researchers have discovered. A recent study published in the Public Library of Science journal PLoS ONE, is the first to identify Miscanthus as a host of the corn rootworm.

The research team, from the University of Illinois Natural History Survey, tested several rootworm beetle populations on Miscanthus, adding rootworm eggs to potted Miscanthus and corn plants in a greenhouse setting. Rootworms from all populations survived to adulthood on the Miscanthus plants, including a strain that is behaviorally resistant to crop rotation. (Rather than remaining true to cornfields, rotation-resistant rootworms also will lay their eggs in soybean fields and other rotated crops, allowing the larvae to feed on corn planted in those fields the following spring.)